fly-sparging: flow not steady

[herman2011]

I am trying a new setup for me:

Mash-tun is 10gal Polarware with false bottom (leaves 1gal foundation water). It has a ball-valve with hose-barb fitting with 3/8" inner-diameter vinyl hose leading to boil-kettle via gravity. Sparge sprinkler (rotating) on top maintaining about 3/4" water layer on grain.

I am having trouble keeping a steady slow flow out of the mash-tun into the boil-kettle. If I keep it at a slow rate it eventually stops. If I open the valve up more it will come flying out of there at much too fast of a rate. If I try to slow it down to the rate I like it will start to get bubbles throughout the line (aeration... yikes) until they clear and then evantually it stops again. Open the valve a little to start it up again and bam, it starts flowing far too fast. Repeat for 1.5 hours until done. It's the pits.

Any ideas?

 

[Jaybird]

Are you doing a full open resirc for about 3-4 min before you close it down and start draining into the boil? How much water are you keeping on top of the grain bed? Do you use rice hulls in your mash?

Cheers
Jay